Battery management circuit, device to be charged, and power management method

ABSTRACT

Battery management circuits include a first charging channel, a Cuk circuit, and a communication control circuit. A battery is charged through the first charging channel based on charging voltage and/or charging current provided by a power supply device. The battery includes a first cell and a second cell coupled in series. The communication control circuit is configured to communicate with the power supply device, to make magnitude of the charging voltage and/or charging current provided by the power supply device match a present charging stage of the battery, and the communication control circuit is further configured to send a drive signal to the Cuk circuit to drive the Cuk circuit to work, to make energy of the first cell and the second cell be transferred through the Cuk circuit to balance voltage of the first cell and voltage of the second cell.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of International Application No.PCT/CN2017/087828, filed on Jun. 9, 2017, which claims priority toInternational Application No. PCT/CN2016/101944, filed on Oct. 12, 2016,and International Application No. PCT/CN2017/073653, filed on Feb. 15,2017, the disclosures of all of which are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

This disclosure relates to the field of charging technology, andparticularly to a battery management circuit, a device to be charged,and a power management method.

BACKGROUND

At present, devices to be charged, such as smart phones, are enjoyingincreasing popularity among consumers. However, the device to be chargedneeds to be charged frequently due to their high power consumption.

In order to improve charging speed, a practical scheme is to charge thedevice to be charged with great current. The greater the current, thehigher the charging speed is. Nevertheless, the heating problem of thedevice to be charged is also getting more serious.

Therefore, requirements on reducing heating of the device to be chargedare proposed.

SUMMARY

According to a first aspect of the disclosure, a battery managementcircuit is provided. The battery management circuit includes a firstcharging channel, a Cuk circuit, and a communication control circuit.Charging voltage and/or charging current is received from a power supplydevice through the first charging channel and provided to a batterydirectly through the first charging channel, where the battery includesa first cell and a second cell coupled in series. When the power supplydevice charges the battery through the first charging channel, thecommunication control circuit is configured to communicate with thepower supply device to make magnitude of the charging voltage and/orcharging current from the power supply device match a present chargingstage of the battery. When voltage of the first cell and voltage ofsecond cell are unbalanced, the communication control circuit is furtherconfigured to send a drive signal to the Cuk circuit to drive the Cukcircuit to work, to make energy of the first cell and the second cell betransferred through the Cuk circuit to balance the voltage of the firstcell and the voltage of the second cell.

According to a second aspect of the disclosure, a device to be chargedis provided. The device to be charged includes a battery including afirst cell and a second cell coupled in series and the batterymanagement circuit according to the first aspect of the disclosure.

According to a third aspect of the disclosure, a battery managementmethod is provided. The battery management method includes thefollowing. Communicate with a power supply device to make magnitude ofcharging voltage and/or charging current provided by the power supplydevice match a present charging stage of a battery, when the powersupply device charges the battery through a first charging channeldirectly, the battery includes a first cell and a second cell coupled inseries. Send a drive signal to a Cuk circuit to drive the Cuk circuit towork, to make energy of the first cell and the second cell betransferred through the Cuk circuit to balance voltage of the first celland voltage of the second cell, when the voltage of the first cell andthe voltage of second cell are unbalanced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram illustrating a charging systemaccording to an implementation of the present disclosure.

FIG. 2 is a schematic diagram illustrating the coupling relationshipbetween a first cell, a second cell, and a Cuk circuit according to animplementation of the present disclosure.

FIG. 3 is an exemplary diagram illustrating a working state of a Cukcircuit according to an implementation of the present disclosure.

FIG. 4 is an exemplary diagram illustrating another working state of aCuk circuit according to an implementation of the present disclosure.

FIG. 5 is a schematic structural diagram illustrating a charging systemaccording to another implementation of the present disclosure.

FIG. 6 is a time sequence diagram illustrating control of switchtransistors of a Cuk circuit according to an implementation of thepresent disclosure.

FIG. 7 is a schematic structural diagram illustrating a charging systemaccording to yet another implementation of the present disclosure.

FIG. 8 is a schematic structural diagram illustrating a device to becharged according to an implementation of the present disclosure.

FIG. 9 is a schematic diagram illustrating a waveform of a pulsatingdirect current (DC) current according to an implementation of thepresent disclosure.

FIG. 10 is a flowchart illustrating a quick charging process accordingto an implementation of the present disclosure.

FIG. 11 is a schematic flowchart illustrating a battery managementmethod according to an implementation of the present disclosure.

DETAILED DESCRIPTION

A power supply device configured to charge a device to be charged hasbeen proposed in the related art. The power supply device works in aconstant-voltage mode, where voltage output by the power supply deviceremains nearly constant, such as 5V, 9V, 12V, 20V, etc.

Voltage output by the power supply device is however not suitable forbeing applied directly to a battery. Instead, the voltage output by thepower supply device needs to be converted by a conversion circuit of thedevice to be charged, so that expected charging voltage and/or chargingcurrent of the battery of the device to be charged can be obtained.

The conversion circuit is configured to convert voltage output by thepower supply device, so as to meet requirements on expected chargingvoltage and/or charging current of the battery.

As an implementation, the conversion circuit can be a chargingmanagement module, such as a charging integrated circuit (IC), which,when the battery is charged, is configured to manage the chargingvoltage and/or charging current of the battery. The conversion circuitfunctions as a voltage feedback module and/or a current feedback module,so as to achieve management of the charging voltage and/or chargingcurrent of the battery.

For example, a charging process of the battery can include at least oneof a trickle charging stage, a constant-current charging stage, and aconstant-voltage charging stage. In the trickle charging stage, theconversion circuit can utilize a current feedback loop to make currentflowing into the battery in the trickle charging stage satisfy expectedcharging current of the battery (such as a first charging current). Inthe constant-current charging stage, the conversion circuit can utilizea current feedback loop to make current flowing into the battery in theconstant-current charging stage satisfy expected charging current of thebattery (such as a second charging current, which may be greater thanthe first charging current). In the constant-voltage charging stage, theconversion circuit can utilize a voltage feedback loop to make voltageapplied to the battery in the constant-voltage charging stage satisfyexpected charging voltage of the battery.

As one implementation, when the voltage output by the power supplydevice is higher than the expected charging voltage of the battery, theconversion circuit can decrease the voltage output by the power supplydevice to make decreased charging voltage meet requirements on theexpected charging voltage of the battery. As another implementation,when the voltage output by the power supply device is lower than theexpected charging voltage of the battery, the conversion circuit canincrease the voltage output by the power supply device to make increasedcharging voltage meet requirements on charging voltage of the battery.

As yet another implementation, the voltage output by the power supplydevice is a constant 5V voltage, for example. When the battery includesa single cell (for example, a lithium battery cell, with a 4.2V chargingcut-off voltage), the conversion circuit (such as a Buck circuit) candecrease (that is, step down) the voltage output by the power supplydevice to make the decreased charging voltage meet requirements oncharging voltage of the battery.

As still another implementation, the voltage output by the power supplydevice is a constant 5V voltage, for example. When the power supplydevice charges a battery with two or more single-cells coupled in series(for example, a lithium battery cell, with a 4.2V charging cut-offvoltage), the conversion circuit (such as a Boost circuit) can increase(that is, step up) the voltage output by the power supply device to makethe increased charging voltage meet requirements on charging voltage ofthe battery.

The conversion circuit is limited by low circuit conversion efficiency,which results in electrical energy that fails to be converteddissipating in the form of heat. The heat can be accumulated inside thedevice to be charged. Since designed space and heat dissipation space ofthe device to be charged are both very small, for example, the physicalsize of a user's mobile terminal is increasingly lighter and thinner,and a large number of electronic components are densely arranged in themobile terminal at the same time, difficulty in designing the conversioncircuit is increased. In addition, it is difficult to remove promptlyheat accumulated inside the device to be charged, which in turn resultsin abnormality of the device to be charged.

For example, heat accumulated inside the conversion circuit may causeheat interference with electronic components near the conversioncircuit, which results in working abnormality of the electroniccomponents. For another example, the heat accumulated inside theconversion circuit may shorten service life of the conversion circuitand the electronic components near the conversion circuit. For yetanother example, the heat accumulated inside the conversion circuit maycause heat interference with the battery, which in turn brings aboutabnormality of charge and discharge of the battery. For still anotherexample, the heat accumulated inside the conversion circuit may raisetemperature of the device to be charged and thus influence userexperience in the charging process. For still another example, the heataccumulated inside the conversion circuit may result in short circuit ofthe conversion circuit itself, causing abnormality of charging since thevoltage output by the power supply device is applied directly to thebattery. In case that the battery is charged with overvoltage for a longtime, battery explosion may even occur, thus putting users at risk.

According to an implementation of the present disclosure, a power supplydevice with adjustable output-voltage is provided. The power supplydevice can acquire state information of a battery. The state informationof a battery can include present power and/or present voltage of thebattery. The power supply device can adjust output-voltage of the powersupply device itself according to the state information of the batteryacquired to meet requirements on charging voltage and/or chargingcurrent of the battery. Output-voltage adjusted by the power supplydevice can be applied directly to the battery to charge the battery(referred to as “direct charging” hereinafter). In addition, in theconstant-current charging stage of the battery, the output-voltageadjusted by the power supply device can be applied directly to thebattery for charging.

The power supply device can function as a voltage feedback module and/ora current feedback module to achieve management of the charging voltageand/or charging current of the battery.

The power supply device can adjust the output-voltage of the powersupply device itself according to the state information of the batteryacquired as follows. The power supply device can acquire the stateinformation of the battery in real time and adjust the output-voltage ofthe power supply device itself according to real-time state informationof the battery acquired each time to meet requirements on the chargingvoltage and/or charging current of the battery.

The power supply device can adjust the output-voltage of the powersupply device itself according to the real-time state information of thebattery acquired as follows. With increase in voltage of the battery inthe charging process, the power supply device can acquire present stateinformation of the battery at different time points in the chargingprocess and adjust in real time the output-voltage of the power supplydevice itself according to the present state information of the battery,so as to meet requirements on the charging voltage and/or chargingcurrent of the battery.

For example, the charging process of the battery can include at leastone of the trickle charging stage, the constant-current charging stage,and the constant-voltage charging stage. In the trickle charging stage,the power supply device can output the first charging current in thetricked charging stage to charge the battery, so as to meet requirementson charging current (the first charging current can be a constant DCcurrent) of the battery. In the constant-current charging stage, thepower supply device can utilize the current feedback loop to make thecurrent output in the constant-current charging stage from the powersupply device to the battery meet requirements of the battery oncharging current, such as the second charging current. The secondcharging current may be a pulsating waveform current and may be greaterthan the first charging current, where a peak value (that is, peakcurrent) of the pulsating waveform current in the constant-currentcharging stage may be greater than magnitude of the constant DC currentin the trickle charging stage, and “constant-current” in theconstant-current charging stage may refer to a situation where the peakvalue or average value of the pulsating waveform current remain nearlyconstant. In the constant-voltage charging stage, the power supplydevice can utilize the voltage feedback loop to make the voltage outputin the constant-voltage charging stage from the power supply device tothe device to be charged (that is, constant DC voltage) remain constant.

For example, in implementations of the present disclosure, the powersupply device can be mainly configured to control the constant-currentcharging stage of the battery of the device to be charged. In otherimplementations, control of the trickle charging stage and theconstant-voltage charging stage of the battery of the device to becharged can also be cooperatively completed by the power supply deviceof the implementation of the present disclosure and an extra chargingchip of the device to be charged. Compared with charging power of thebattery received in the constant-current charging stage, charging powersof the battery received in the trickle charging stage and in theconstant-voltage charging stage are lower, so conversion efficiency lossand heat accumulation of the charging chip of the device to be chargedare acceptable. It should be noted that, in implementations of thepresent disclosure, the constant-current charging stage or theconstant-current stage can refer to a charging mode of controllingoutput-current of the power supply device but does not require that theoutput-current of the power supply device remain completely constant,and may be, for example, a peak value or an average value of a pulsatingwaveform current output by the power supply device remaining nearlyconstant, or remaining nearly constant within a certain time period.Practically, for example, in the constant-current charging stage, thepower supply device usually charges the battery in a multi-stageconstant current charging manner.

Multi-stage constant current charging can include N constant-currentstages, where N is an integer not less than two (N>=2). In themulti-stage constant current charging, a first stage of charging beginswith a pre-determined charging current. The N constant-current stages ofthe multi-stage constant current charging are executed in sequence fromthe first stage to the N^(th) stage. When a previous constant-currentstage ends and a next constant-current stage begins, the peak value oraverage value of the pulsating waveform current may decrease. Whenvoltage of the battery reaches a threshold value of charging cut-offvoltage, the multi-stage constant current charging proceeds to asubsequent constant-current stage, that is, the previousconstant-current stage ends and the next constant-current stage begins.Current conversion between two adjacent constant-current stages may begradual or in a step-like manner.

In addition, in case that the current output by the power supply deviceis a pulsating DC current, the constant-current mode can refer to acharging mode of controlling a peak value or an average value of thepulsating DC current, that is, controlling the peak value of the currentoutput by the power supply device not to be greater than currentcorresponding to the constant-current mode. Furthermore, in case thatthe current output by the power supply device is an alternating current(AC) current, the constant-current mode can refer to a charging mode ofcontrolling a peak value of the AC current.

In addition, it should be noted that, in the implementations of thepresent disclosure, the device to be charged can be a terminal. The“terminal” can include but is not limited to a device configured througha wired line and/or a wireless interface to receive/transmitcommunication signals. Examples of the wired line may include, but arenot limited to, at least one of a public switched telephone network(PSTN), a digital subscriber line (DSL), a digital cable, a directconnection cable, and/or other data connection lines or networkconnection lines. Examples of the wireless interface may include, butare not limited to, a wireless interface with a cellular network, awireless local area network (WLAN), a digital television network (suchas a digital video broadcasting-handheld (DVB-H) network), a satellitenetwork, an AM-FM broadcast transmitter, and/or with other communicationterminals. A communication terminal configured to communicate through awireless interface may be called a “wireless communication terminal”, a“wireless terminal”, and/or a “mobile terminal”. Examples of a mobileterminal may include, but are not limited to, a satellite or cellulartelephone, a personal communication system (PCS) terminal capable ofcellular radio telephone, data processing, fax, and/or datacommunication, a personal digital assistant (PDA) equipped with radiotelephone, pager, Internet/Intranet access, web browsing, notebook,calendar, and/or global positioning system (GPS) receiver, and/or otherelectronic devices equipped with radio telephone capability such as aconventional laptop or a handheld receiver. In addition, in theimplementation of the present disclosure, the device to be charged orterminal can also include a power bank. The power bank can be charged bythe power supply device and thus store energy to charge other electronicdevices.

Furthermore, in an implementation of the present disclosure, when apulsating waveform voltage output by the power supply device is applieddirectly to a battery of the device to be charged to charge the battery,charging current can be represented in the form of a pulsating wave(such as a steamed bun wave). It can be understood that, the chargingcurrent can charge the battery in an intermittent manner. Period of thecharging current can vary with frequency of an input AC such as an ACpower grid. For instance, frequency corresponding to the period of thecharging current is N times (N is a positive integer) or N times thereciprocal of frequency of a power grid. Additionally, when the chargingcurrent charges the battery in an intermittent manner, current waveformcorresponding to the charging current can include one pulse or one groupof pulses synchronized with the power grid.

As an implementation, in an implementation of the present disclosure,when the battery is charged (such as in at least one of the tricklecharging stage, the constant-current charging stage, and theconstant-voltage charging stage), the battery can receive a pulsating DC(direction remains constant, and magnitude varies with time), an AC(both direction and magnitude vary with time), or a DC (that is, aconstant DC, neither magnitude nor direction varies with time) output bythe power supply device.

As to a conventional device to be charged, the device to be chargedusually has only one single cell. When the single cell is charged withgreat charging current, heating of the device to be charged is serious.In order to guarantee charging speed and reduce heating of the device tobe charged, structure of the cell of the device to be charged ismodified in the implementations of the present disclosure. A batterywith cells coupled in series, together with a battery management circuitthat is able to conduct direct charging on the battery with cellscoupled in series, is provided. Since, to achieve equal charging speed,charging current of the battery with cells coupled in series is 1/N timethe magnitude of charging current of the battery with one single cell,where N represents the number of cells coupled in series of the deviceto be charged. For the equal charging speed, the battery managementcircuit of the implementations of the present disclosure acquiressmaller charging current from an external power supply device, therebyreducing heating in the charging process.

FIG. 1 is a schematic structural diagram illustrating a charging systemaccording to an implementation of the present disclosure. The chargingsystem includes a power supply device 10, a battery management circuit20, and a battery 30. The battery management circuit 20 can beconfigured to manage the battery 30. As an implementation, the batterymanagement circuit 20 can be configured to manage a charging process ofthe battery 30, such as selecting a charging channel, controllingcharging voltage and/or charging current, and so on. As anotherimplementation, the battery management circuit 20 can be configured tomanage cells of the battery 30, such as balancing voltage between thecells of the battery 30.

The battery management circuit 20 can include a first charging channel21 and a communication control circuit 23.

Through the first charging channel 21, charging voltage and/or chargingcurrent can be received from the power supply device 10 and applied tothe battery 30 (that is, across the battery 30) for charging.

In other words, through the first charging channel 21, direct chargingcan be conducted on the battery 30 by applying directly the chargingvoltage and/or charging current received from the power supply device 10to the battery 30. “Direct charging” is elaborated in the wholedisclosure and will not be repeated herein. The first charging channel21 can be referred to as a direct charging channel. The direst chargingchannel does not need to be provided with a conversion circuit such as acharging IC. That is to say, unlike a conventional charging channel,through the direct charging channel, the charging voltage and/orcharging current received from the power supply device do not need to beconverted and then applied to the battery. Instead, through the directcharging channel, the charging voltage and/or charging current receivedfrom the power supply device can be directly applied to the battery.

The first charging channel 21 can be, for example, a wire.Alternatively, the first charging channel 21 can be provided with othercircuit components unrelated to charging voltage and/or charging currentconversion. For instance, the battery management circuit 20 includes thefirst charging channel 21 and a second charging channel. The firstcharging channel 21 can be provided with a switch component configuredto switch between charging channels, which will be described in detailin FIG. 7.

The power supply device 10 can be the power supply device withadjustable output-voltage mentioned above. However, the types of thepower supply device 10 are not limited herein. For example, the powersupply device 10 can be a device specially configured to charge such asan adaptor, a power bank, etc., or other devices that are able toprovide both power and data service such as a computer.

The battery 30 according the implementation of the present disclosurecan include multiple cells coupled in series (at least two cells). Thecells coupled in series can be configured to divide the charging voltageprovided by the power supply device 10 in the charging process. Asillustrated in FIG. 1, a first cell 31 a and a second cell 31 b can beany two of the multiple cells or any two groups of the multiple cells.Exemplarily, when the first cell 31 a (or the second cell 31 b) includesa group of cells, all cells in this cell-group can be coupled in seriesor in parallel. The coupling manners of the cells are not limitedherein.

The battery 30 can include one battery or multiple batteries. That is tosay, the cells coupled in series according to the implementation of thepresent disclosure can be packaged into one battery pack to form onebattery or be packaged into multiple battery packs to form multiplebatteries. For instance, the battery 30 can be one battery. The onebattery includes the first cell 31 a and the second cell 31 b coupled inseries. For another instance, the battery 30 can include two batteries.One of the two batteries includes the first cell 31 a, and the other oneof the two batteries includes the second cell 31 b.

When the power supply device 10 charges the battery 30 through the firstcharging channel 21, the communication control circuit 23 can beconfigured to communicate with the power supply device 10 to makemagnitude of the charging voltage and/or charging current received fromthe power supply device 10 match a present charging stage of the battery30, or make magnitude of the charging voltage and/or charging currentreceived from the power supply device 10 meet requirements on thecharging voltage and/or charging current in the present charging stageof the battery 30.

As mentioned above, the first charging channel 21 is a direct chargingchannel and the charging voltage and/or charging current received fromthe power supply device 10 can be applied directly to the battery 30through the first charging channel 21. In order to achieve directcharging, the implementations of the present disclosure introduce in thebattery management circuit 20 a control circuit with a communicationfunction, that is, the communication control circuit 23. Thecommunication control circuit 23 can be configured to keep communicatingwith the power supply device 10 in a direct charging process to form aclosed-loop feedback mechanism, so as to enable the power supply device10 to acquire the state information of the battery in real time, thusadjusting continuously the charging voltage and/or charging currentflowing into the first charging channel to guarantee that magnitude ofthe charging voltage and/or charging current received from the powersupply device 10 matches the present charging stage of the battery 30.

The present charging stage of the battery 30 can be any one of thetrickle charging stage, the constant-current charging stage, and theconstant-voltage charging stage.

In the trickle charging stage of the battery 30, the communicationcontrol circuit 23 can be configured to communicate with the powersupply device 10, so that the power supply device 10 can adjust chargingcurrent provided to the first charging channel 21, to make the chargingcurrent match charging current corresponding to the trickle chargingstage, or make the charging current to meet requirements on chargingcurrent in the trickle charging stage of the battery 30.

In the constant-voltage charging stage of the battery 30, thecommunication control circuit 23 can be configured to communicate withthe power supply device 10, so that the power supply device 10 canadjust charging voltage provided to the first charging channel 21, tomake the charging voltage match charging voltage corresponding to theconstant-voltage charging stage, or make the charging voltage meetrequirements on charging voltage in the constant-voltage charging stageof the battery 30.

In the constant-current charging stage of the battery 30, thecommunication control circuit 23 can be configured to communicate withthe power supply device 10, so that the power supply device 10 canadjust charging current provided to the first charging channel 21, tomake the charging current match charging current corresponding to theconstant-current charging stage, or make the charging current meetrequirements on charging current in the constant-current charging stageof the battery 30.

In implementations of the present disclosure, content communicated andcommunication methods between the communication control circuit 23 andthe power supply device 10 are not limited. The above aspects will bedescribed in detail hereinafter in conjunction with specificimplementations and will not be repeated herein.

The battery management circuit 20 can further include a Cuk circuit 22.In case that voltage of the first cell 31 a and voltage of the secondcell 31 b are unbalanced, the communication control circuit 23 isconfigured to send a drive signal to the Cuk circuit 22 to drive the Cukcircuit 22 to work, to make energy of the first cell 31 a and the secondcell 31 b be transferred through the Cuk circuit 22 to balance thevoltage of the first cell and the voltage of the second cell. The cukcircuit 22 can be comprehended as a type of DC/DC converter that has anoutput voltage magnitude that is either greater than or less than theinput voltage magnitude.

The battery management circuit according to the implementation of thepresent disclosure can be configured to conduct direct charging on thebattery. In other words, the battery management circuit according to theimplementation of the present disclosure is a battery management circuitthat supports a direct charging architecture. In the direct chargingarchitecture, the direct charging channel does not need to be providedwith a conversion circuit, which in turn reduces heating of the deviceto be charged in the charging process.

Direct charging scheme can reduce heating of the device to be charged inthe charging process to some extent. However, when charging currentreceived from the power supply device 10 is excessive, such as anoutput-current of the power supply device 10 reaching a magnitudebetween 5 A and 10 A, heating of the battery management circuit 20 isstill serious, and thus safety problems may occur.

In order to guarantee charging speed and further reduce heating of thedevice to be charged in the charging process, structure of the batteryis modified in the implementation of the present disclosure. A batterywith cells coupled in series is provided. Compared with a battery withone single cell, to achieve an equal charging speed, charging current ofthe battery with cells coupled in series is 1/N time the magnitude ofcharging current of a battery with one single cell, where N representsthe number of cells coupled in series of the device to be charged. Thatis to say, as to an equal charging speed, the implementation of thepresent disclosure can substantially reduce magnitude of chargingcurrent, thereby further reducing heating of the device to be charged inthe charging process.

For example, as to a single-cell battery of 3000 mAh, a 9 A (Ampere)charging current is needed to reach a 3 C (Coulomb) charging speed. Inorder to reach an equal charging speed and reduce heating of the deviceto be charged in the charging process at the same time, two cells, eachof 1500 mAh, can be coupled in series to replace the single cell of 3000mAh. As a result, only a 4.5 A charging current is needed to reach the3C charging speed. In addition, compared with the 9 A charging current,the 4.5 A charging current produces substantially less heat than the 9 Acharging current.

In addition, the power management circuit in the implementation of thepresent disclosure can be configured to balance voltage between cellscoupled in series and make parameters of the cells coupled in series beapproximate to facilitate unified management of cells of the battery.Furthermore, in case that the battery includes multiple cells, keepingparameters between the cells consistent can improve overall performanceand service life of the battery.

It should be noted that, since a direct charging manner is adopted tocharge the battery 30 with multiple cells coupled in series though thefirst charging channel 21, charging voltage received from the powersupply device 10 needs to be higher than total voltage of the battery30. In general, working voltage of a single cell is between 3.0V and4.35V. In case of double cells coupled in series, when the firstcharging channel 21 (that is, the direct charging channel) is adopted inthe charging process, output-voltage of the power supply device 10 canbe set equal to or higher than 10V.

A Cuk circuit can sometimes be referred to as a Cuk chopping circuit.The Cuk circuit is frequently configured to conduct DC/DC conversion.Therefore, the Cuk circuit can sometimes be referred to as a Cukconverter.

Referring to FIG. 2, an exemplary Cuk circuit includes at least oneswitch transistor, a first inductor and a second inductor, and acapacitor coupled between the first inductor and the second inductor,the first inductor is further coupled with a positive electrode of thefirst cell and the second inductor is further coupled with a negativeelectrode of the second cell, and the at least one switch transistor hasone end coupled between the capacitor and one inductor and another endcoupled with an electrode of the first cell or the second cell.

As one example, the at least one switch transistor includes a firstswitch transistor and a second switch transistor, the first switchtransistor has one end coupled between the capacitor and the firstinductor, another end coupled with a negative electrode of the firstcell, and still another end coupled with the communication circuit; thesecond switch transistor has one end coupled between the capacitor andthe second inductor, another end coupled with a positive electrode ofthe second cell, and still another end coupled with the communicationcircuit. The communication control circuit is configured to send thedrive signal to the first switch transistor and the second switchtransistor respectively in a predetermined time sequence to controldirection and speed of energy transfer between the first cell and thesecond cell.

Details of the Cuk circuit and energy transfer between the first celland the second cell will be given below.

In implementations of the present disclosure, directions of energytransfer between the first cell 31 a and the second cell 31 b duringworking of the Cuk circuit 22 are not limited. Energy can be transferredunidirectionally or bi-directionally. The following will illustrate abi-directional energy transfer process between the first cell 31 a andthe second cell 31 b with reference to FIG. 2.

As illustrated in FIG. 2, one side of the Cuk circuit 22 is coupled withthe first cell 31 a, and the other side of the Cuk circuit 22 is coupledwith the second cell 31 b. The first cell 31 a and the second cell 31 bare isolated with each other through a capacitor C, and energy can betransferred between the first cell 31 a and the second cell 31 b throughthe capacitor C. Capacitance value of the capacitor C is not limitedherein. For example, the capacitance value the capacitor C can be setgreat enough for the capacitor C to be consistently in a steady stateduring working of the Cuk circuit 22, where voltage across the capacitorC remains nearly constant. An inductor L1 is set near the first cell 31a, and an inductor L2 is set near the second cell 31 b. Thanks to theinductor L1 and the inductor L2, the pulsation of current in the Cukcircuit can be substantially reduced. In actual circuit arrangements,distance between the inductor L1 and the inductor L2 can be set veryshort, such that the inductor L1 and the inductor L2 can produce mutualinductance, thereby further reducing pulsation of current in the Cukcircuit 22. In addition, the Cuk circuit 22 can include a switchtransistor Q1 and a switch transistor Q2, and the switch transistor Q1and the switch transistor Q2 each can be a MOS (metal oxidesemiconductor) transistor. When the voltage of the first cell 31 a andthe voltage of the second cell 31 b are balanced, the switch transistorQ1 and the switch transistor Q2 are both off. In this case, the Cukcircuit 22 does not work. When the voltage of the first cell 31 a andthe voltage of the second cell 31 b are unbalanced, the communicationcontrol circuit 23 can be configured to send a drive signal to theswitch transistor Q1 and the switch transistor Q2 respectively in acertain time sequence, to control the on-off state of the switchtransistor Q1 and the switch transistor Q2, so as to control directionand speed of energy transfer between the first cell 31 a and the secondcell 31 b.

In case that the voltage of the first cell 31 a is higher than thevoltage of the second cell 31 b, the communication control circuit 23needs to transfer energy of the first cell 31 a to the second cell 31 b.The communication control circuit 23 can execute the following controllogic alternately: the switch transistor Q1 is on and the switchtransistor Q2 is off; the switch transistor Q1 is off and the switchtransistor Q2 is on.

When the switch transistor Q1 is on and the switch transistor Q2 is off,as illustrated in FIG. 3, the first cell 31 a and the inductor L1 form aclosed circuit (referred to as a closed circuit 1 hereinafter); thecapacitor C, the inductor L2, and the second cell 31 b form anotherclosed circuit (referred to as a closed circuit 2 hereinafter). In theclosed circuit 1, the first cell 31 a provides energy for the inductorL1 through current iL1 to make the inductor L1 store energy. In theclosed circuit 2, the capacitor C discharges, so as to provide energyfor the second cell 31 b and store energy for the inductor L2.

When the switch transistor Q1 is off and the switch transistor Q2 is on,as illustrated in FIG. 4, the first cell 31 a, the inductor L1, and thecapacitor C form a closed circuit (referred to as a closed circuit 3hereinafter); the inductor L2 and the second cell 31 b form anotherclosed circuit (referred to as a closed circuit 4 hereinafter). In theclosed circuit 3, the first cell 31 a and the inductor L1 provide energyto charge the capacitor C. In the closed circuit 4, the inductor L2discharges stored energy to the second cell 31 b.

Through the above-mentioned processes, energy of the first cell 31 a canbe transferred to the second cell 31 b. From the perspective of cellpower (“power” for short), power of the first cell 31 a gets lower andpower of the first cell 31 b gets higher, that is, power of the firstcell 31 a is transferred to the second cell 31 b.

It can be seen from FIG. 2 that, the Cuk circuit 22 in theimplementation of the present disclosure is a Cuk circuit with asymmetric structure. In case that the voltage of the second cell 31 b ishigher than the voltage of the first ell 31 a and energy of the secondcell 31 b needs to be transferred to the first cell 31 a, thecommunication control circuit 23 can control on-off states of the switchtransistor Q1 and the switch transistor Q2 in a transistor controlmanner opposite to that described above, so as to realize energytransfer from the second cell 31 b to the first cell 31 a.

It should be understood that, FIG. 2 to FIG. 4 illustrates an example ofa bi-directional energy transfer between the first cell 31 a and thesecond cell 31 b with the Cuk circuit 22 that is a Cuk circuit with asymmetric structure. The implementation of the present disclosure is notlimited to the above example. The Cuk circuit 22 can also be a Cukcircuit with an asymmetric structure, which is only responsible forenergy-transfer from the first cell 31 a to the second cell 31 b orenergy-transfer from the second cell 31 b to the first cell 31 a. Forexample, the switch transistor Q2 of FIG. 2 can be replaced by afree-wheeling diode. By means of such Cuk circuit, energy transfer fromthe first cell 31 a to the second cell 31 b can be achieved, but it isunable to achieve energy transfer from the second cell 31 b to the firstcell 31 a. For another example, the switch transistor Q1 of FIG. 2 canbe replaced by a free-wheeling diode. With such Cuk circuit, energytransfer from the second cell 31 b to the first cell 31 a can beachieved, but it is unable to achieve energy transfer from the firstcell 31 a to the second cell 31 b.

It should be understood that, imbalance between the voltage of the firstcell 31 a and the voltage of the second cell 31 b can be defined invarious manners and is not limited herein. As an implementation, as longas present voltage and/or present power of the first cell 31 a andpresent voltage and/or present power of the second cell 31 b are notequal, the voltage of the first cell 31 a and the voltage of the secondcell 31 b are determined as unbalanced. As another implementation, theimbalance between the voltage of the first cell 31 a and the voltage ofthe second cell 31 b can be defined as the following. The presentvoltage and/or present power of the first cell 31 a and the presentvoltage and/or present power of the second cell 31 b are not equal, anddifference between the present voltage and/or present power of the firstcell 31 a and the present voltage and/or present power of the secondcell 31 b satisfies a certain preset condition, such as the differencebetween the present voltage and/or power of the first cell 31 a and thepresent voltage and/or power of the second cell 31 b being greater thana preset threshold value. Similarly, the communication control circuit23 balancing the voltage of the first cell 31 a and the voltage of thesecond cell 31 b through the Cuk circuit 22 can be defined as follows.The communication control circuit 23 adjusts the voltage of the firstcell 31 a and the voltage of the second cell 31 b to make the twobalanced. Alternatively, the communication control circuit 23 balancingthe voltage of the first cell 31 a and the voltage of the second cell 31b through the Cuk circuit 22 can be defined as follows. Thecommunication control circuit 23 reduces the difference between thepresent voltage and/or present power of the first cell 31 a and thepresent voltage and/or present power of the second cell 31 b to a valueless than a certain preset threshold value.

In an implementation, as illustrated in FIG. 5, the communicationcontrol circuit 23 can be coupled with a positive electrode of the firstcell 31 a and a positive electrode the second cell 31 b, so as to detectthe present voltage of the first cell 31 a and the present voltage thesecond cell 31 b. When difference between the present voltage of thefirst cell 31 a and the present voltage of the second cell 31 b isgreater than a preset threshold value, the communication control circuit23 is configured to send a drive signal to the Cuk circuit 22 to drivethe Cuk circuit 22 to work. Alternatively, the communication controlcircuit 23 can be further configured to monitor the present power of thefirst cell 31 a and the present power of the second cell 31 b. Whendifference between the present power of the first cell 31 a and thepresent power of the second cell 31 b is greater than a preset thresholdvalue, the communication control circuit 23 is configured to send adrive signal to the Cuk circuit 22 to drive the Cuk circuit 22 to work.

The drive signal can be, for example, a Pulse Width Modulation (PWM)signal, or other types of control signals that can control on-off statesof a switch transistor.

The form of the communication control circuit 23 is not limited inimplementations of the present disclosure. For instance, thecommunication control circuit 23 can include a microcontroller unit(MCU) and a switch-transistor driver (such as an MOS transistor driver).The MCU can be configured to communicate with the power supply device 10and can be further configured to determine whether energy transferbetween the first cell 31 a and the second cell 31 b is conducted or notand determine a direction of energy-transfer between the first cell 31 aand the second cell 31 b. In case that the MCU determines the energytransfer between the first cell 31 a and the second cell 31 b to beconducted and the direction of the energy transfer between the firstcell 31 a and the second cell 31 b, the MCU can be configured to controlan on-off time sequence of the switch transistor Q1 and an on-off timesequence of the switch transistor Q2 through the switch-transistordriver, so as to achieve energy transfer between the first cell 31 a andthe second cell 31 b with the Cuk circuit.

Optionally, in some implementations, the communication control circuit23 can be further configured to adjust duty cycle of the drive signal toadjust current in the Cuk circuit 22 during working of the Cuk circuit22.

It should be understood that, the higher the current in the Cuk circuit22, higher speed of the energy transfer between the first cell 31 a andthe second cell 31 b (or power moving speed) results in the higherefficiency in balancing the voltage of the first cell 31 a and thevoltage of the second cell 31 b.

The battery management circuit 20 in the implementation of the presentdisclosure can be configured to adjust the speed of the energy transferbetween the first cell 31 a and the second cell 31 b, thereby making thebattery management circuit 20 manage the voltage of the first cell 31 aand the voltage of the second cell 31 b in a smarter manner.

As illustrated in FIG. 6, on the left is a schematic diagram of anon-off time sequence of the switch transistor Q1, an on-off timesequence of the switch transistor Q2, a waveform of current iL1, and awaveform of current iL2 when the duty cycle of the drive signal is afirst duty cycle; on the right is a schematic diagram of the on-off timesequence of the switch transistor Q1, the on-off time sequence of theswitch transistor Q2, a waveform of current iL1, and a waveform ofcurrent iL2 when the duty cycle of the drive signal is a second dutycycle. The first duty cycle is greater than the second duty cycle.

It can be seen from FIG. 6 that, a higher duty cycle of the drive signalcorresponds to a longer switch-on time of the switch transistor Q1 and alonger switch-on time of the switch transistor Q2, a greater current inthe Cuk circuit (that is, current iL1 and current iL2), and a fasterenergy transfer speed between the first cell 31 a and the second cell 31b.

Factors that need to be taken into account when the communicationcontrol circuit 23 adjusts the duty cycle of the drive signal are notlimited herein.

As an implementation, when the first cell 31 a and the second cell 31 bare in a working state, the communication control circuit 23 can beconfigured to decrease the duty cycle of the drive signal to avoid lowpower supply quality because of fast energy transfer between cells. Whenthe first cell 31 a and the second cell 31 b are in a non-working state(that is, idle state), the communication control circuit 23 can beconfigured to increase the duty cycle of the drive signal.

As another implementation, one of the first cell 31 a and the secondcell 31 b is a master cell and the other one is a slave cell. Whensystem of the device to be charged is charged, a single-cell powersupply scheme can be adopted, that is, the master cell works and theslave cell does not work. When difference between present voltage and/orpresent power of the master cell and present voltage and/or presentpower of the slave cell is great, it means that the master cell isheavily loaded. In this case, the communication control circuit 23 canbe configured to increase the duty cycle of the drive signal to increasethe speed of energy transfer from the slave cell to the master cell,thereby avoiding power interruption of the system caused by rapiddecrease in the voltage of the master cell. On the contrary, when thedifference between the present voltage and/or present power of themaster cell and the present voltage and/or present power of the slavecell is small, it means that the master cell is lightly loaded. In thiscase, the communication control circuit 23 can be configured to decreasethe duty cycle of the drive signal to transfer energy from the slavecell to the master cell at a lower speed. Lower energy transfer speedmeans smaller current in the Cuk circuit 22, thereby reducing heating ofthe Cuk circuit 22.

Optionally, in some implementations, as illustrated in FIG. 5, thebattery management circuit 20 further includes a current detectingcircuit 41 a and a current detecting circuit 41 b configured to detectthe current in the Cuk circuit 22. The communication control circuit 23can be configured to adjust the duty cycle of the drive signal to adjustthe current of the Cuk circuit mentioned above as follows. Thecommunication control circuit 23 determines a target value of thecurrent in the Cuk circuit 22, according to the difference between thepresent power and/or present voltage of the first cell 31 a and thepresent power and/or present voltage of the second cell 31 b; thecommunication control circuit 23 adjusts the duty cycle of the drivesignal to make the current in the Cuk circuit 22 detected by the currentdetecting circuit 41 a and the current detecting circuit 41 b reach thetarget value.

As illustrated in FIG. 3 and FIG. 4, the current in the Cuk circuit 22can include current iL1 and iL2. It should be understood that, FIG. 5illustrates an example in which the battery management circuit 20includes two current detecting circuits, that is, the current detectingcircuit 41 a and the current detecting circuit 41 b, where the currentdetecting circuit 41 a is configured to detect current iL1 in the Cukcircuit 22 and the current detecting circuit 41 b is configured todetect current iL2 in the Cuk circuit 22. However, the implementation ofthe present disclosure is not limited to the above example. In someimplementations, the battery management circuit 20 can include only oneof the two current detecting circuits 41 a and 41 b.

Suppose one of the first cell 31 a and the second cell 31 b is a mastercell and the other one is a slave cell, where the master cell isconfigured to supply power to a system. When difference between thepresent voltage and/or present power of the first cell 31 a and thepresent voltage and/or present power of the second cell 31 b is great,it means that the master cell is heavily loaded, and the current in theCuk circuit 22 can be increased in this case. When the differencebetween the present voltage and/or present power of the first cell 31 aand the present voltage and/or present power of the second cell 31 b issmall, it means that the master cell is lightly loaded, and the currentin the Cuk circuit 22 can be decreased in this case.

The manner in which the communication control circuit 23 determines thetarget value of the current in the Cuk circuit 22 according to thedifference between the present voltage and/or present power of the firstcell 31 a and the present voltage and/or present power of the secondcell 31 b is not limited herein. As an implementation, a correspondencerelationship between the difference between the present voltage and/orpresent power of the first cell 31 a and the present voltage and/orpresent power of the second cell 31 b and the current in the Cuk circuit22 can be preset. In practice, the target value of the current in theCuk circuit 22 corresponding to the difference between the presentvoltage and/or present power of the first cell 31 a and the presentvoltage and/or present power of the second cell 31 b can be determinedaccording to the above correspondence relationship. As anotherimplementation, the difference between the present voltage and/orpresent power of the first cell 31 a and the present voltage and/orpresent power of the second cell 31 b and other factors such astemperature of the device to be charged (or the battery of the device tobe charged) can be comprehensively taken into account to determine thetarget value of the current in the Cuk circuit 22. For example, when thedifference between the present voltage and/or present power of the firstcell 31 a and the present voltage and/or present power of the secondcell 31 b is great, but the temperature of the battery of the device tobe charged is also high, the target value of the current in the Cukcircuit 22 can be set smaller to avoid further increase in temperatureof the device to be charged (or the battery of the device to becharged). When the difference between the present voltage and/or presentpower of the first cell 31 a and the present voltage and/or presentpower of the second cell 31 b is great and the temperature of thebattery of the device to be charged is low, the target value of thecurrent in the Cuk circuit 22 can be set greater to increase efficiencyin balancing the voltage of the first cell 31 a and the voltage of thesecond cell 31 b.

Optionally, in some implementations, as illustrated in FIG. 7, thebattery management circuit 20 can further include a second chargingchannel 24. The second charging channel is provided with a boost circuit25. The boost circuit 25 is configured to receive initial voltage fromthe power supply device 10 and increase the initial voltage to a targetvoltage to charge the battery 30 according to the target voltage whenthe power supply device 10 charges the battery 30 through the secondcharging channel 24. The initial voltage is lower than total voltage ofthe battery 30 and the target voltage is higher than the total voltageof the battery 30. The communication control circuit 23 is furtherconfigured to control switching between the first charging channel 21and the second charging channel 24.

It can be understood from above that, direct charging is conducted oncells of the battery 30 through the first charging channel 21, anddirect charging requires that charging voltage received from the powersupply device 10 be higher than total voltage of cells coupled in seriesof the battery. For example, as to two cells coupled in series, supposepresent voltage of each cell is 4V, when the two cells are chargedthrough the first charging channel 21, the charging voltage receivedfrom the power supply device 10 is required to be at least higher than8V. However, output-voltage of a conventional power supply device isusually unable to reach 8V (for example, a conventional adaptor usuallyprovides an output-voltage of 5V), which results in the conventionalpower supply device being unable to charge the battery 30 through thefirst charging channel 21. In order to make the above direct chargingcircuit be compatible with the conventional power supply device, such asa conventional power adaptor, the second charging channel 24 is providedherein. The second charging channel 24 is provided with a boost circuit25, and the boost circuit 25 is configured to increase the initialvoltage received from the power supply device 10 to a target voltage tomake the target voltage be higher than the total voltage of the battery30, so as to solve the problem of the conventional power supply devicebeing unable to charge the battery 30 with multiple cells coupled inseries according to the implementations of the disclosure.

The configuration of the boost circuit 25 is not limited herein. Forinstance, a Boost circuit or a charge pump can be adopted to increasevoltage. Optionally, in some implementations, a conventional chargingchannel design can be adopted for the second charging channel 24, thatis, the second charging channel 24 can be provided with a conversioncircuit, such as a charging IC. The conversion circuit can be configuredto take constant-voltage and constant-current control of the chargingprocess of the battery 30 and adjust (such as increase or decrease) theinitial voltage received from the power supply device 10 according toactual needs. In the implementations of the disclosure, the initialvoltage received from the power supply device 10 can be increased to thetarget voltage by utilizing a boost function of the conversion circuit.

The communication control circuit 23 can achieve switching between thefirst charging channel 21 and the second charging channel 24 through aswitch component. Specifically, as illustrated in FIG. 7, the firstcharging channel 21 is provided with a switch transistor Q5. When thecommunication control circuit 23 controls the switch transistor Q5 toswitch-on, the first charging channel 21 works and direct charging isconducted on the battery 30 through the first charging channel 21. Whenthe communication control circuit 23 controls the switch transistor Q5to switch-off, the second charging channel 24 works and charging isconducted on the battery 30 through the second charging channel 24.

In an implementation of the disclosure, a device to be charged isprovided. As illustrated in FIG. 8, the device to be charged 40 caninclude the battery management circuit 20 and the battery 30 describedabove.

At present, a single-cell power supply scheme is generally adoptedduring charging of a system of a device to be charged (such as aterminal). Multiple cells coupled in series are proposed inimplementations of the disclosure. Total voltage of the multiple cellsis high and is therefore unsuitable to be used directly to supply powerto the device to be charged. In order to solve this problem, a practicalscheme is to adjust working voltage of the system of the device to becharged, so as to enable the system of the device to be charged tosupport multiple-cell power supply. However, this scheme results in toomany modifications to the device to be charged and high cost.

Optionally, in some implementations, the device to be charged 40 can beprovided with a buck circuit, so as to make decreased voltage meetrequirements of the device to be charged 40 on power supply voltage.

For example, working voltage of a single cell is 3.0V to 4.35V. In orderto guarantee normal power supply voltage of the system of the device tobe charged, the buck circuit can decrease (that is, step down) the totalvoltage of the battery 30 to a value between 3.0V and 4.35V. The buckcircuit can be implemented in various manners, such as a Buck circuit, acharge pump, etc., to decrease voltage.

Optionally, in other implementations, a power supply circuit of thedevice to be charged 40 has an input end that can be coupled with bothends of any one single cell of the battery 30. The power supply circuitcan supply power to the system of the device to be charged 40 accordingto voltage of the one single cell.

It should be understood that, voltage decreased by the buck circuit mayhave ripples and in turn influence power supply quality of the device tobe charged. The implementation of the disclosure still adopts one singlecell to supply power to the system of the device to be charged, due tosteady voltage output by one single cell. Therefore, in theimplementation of the disclosure, while a problem of how to supply powerin a multiple-cell scheme is solved, power supply quality of the systemof the device to be charged can be guaranteed.

When one single cell is adopted to supply power, imbalance of voltagebetween different cells of the battery 30 may occur. The imbalance ofvoltage between different cells can cause difficulty in batterymanagement. In addition, difference in parameters of cells of thebattery can result in decrease in service life of the battery. In theimplementation of the disclosure, the Cuk circuit 22 is configured tobalance voltage between cells, thereby keeping voltage between the cellsof the battery 30 balanced even if the above single-cell power supplyscheme is adopted.

With output power of the power supply device increasing, when the powersupply device charges the cells of the device to be charged, lithiumprecipitation may occur, which decreases service life of the cells.

In order to improve reliability and safety of the cells, in someimplementations, the power supply device 10 can be controlled to outputa pulsating DC current (also referred to as a one-way pulsatingoutput-current, a pulsating waveform current, or a steamed bun wavecurrent). Since the direct charging manner is adopted to charge thebattery 30 through the first charging channel 21, the pulsating DCcurrent received from the power supply device 10 can be applied directlyto the battery 30. As illustrated in FIG. 9, magnitude of the pulsatingDC current varies periodically. Compared with a constant DC current, thepulsating DC current can reduce lithium precipitation of a cell, therebyincreasing service life of the cell. In addition, compared with theconstant DC current, the pulsating DC current can decrease possibilityand intensity in arcing of a contact of a charging interface, therebyincreasing service life of the charging interface.

Adjusting charging current output by the power supply device 10 to thepulsating DC current can be implemented in various manners. For example,a primary filtering circuit and a secondary filtering circuit of thepower supply device 10 can be removed, so as to make the power supplydevice 10 output the pulsating DC current.

Optionally, in some implementations, the charging current received fromthe power supply device 10 by the first charging channel 21 can be an ACcurrent, for example, a primary filtering circuit, a secondaryrectifying circuit, and a secondary filtering circuit of the powersupply device 10 can be removed to make the power supply device 10output the AC current. The AC current can also reduce lithiumprecipitation of the cell and increase the service life of the cell.

Optionally, in some implementations, the power supply device 10 isselectively operable in a first charging mode or a second charging mode.Charging speed of the power supply device 10 charging the battery 30 inthe second charging mode is faster than that of the power supply device10 charging the battery 30 in the first charging mode. In other words,compared with the power supply device 10 working in the first chargingmode, the power supply device 10 working in the second charging modetakes less time to charge a battery of the same capacity. In addition,in some implementations, in the first charging mode, the power supplydevice 10 charges the battery 30 through the second charging channel 24;in the second charging mode, the power supply device 10 charges thebattery 30 through the first charging channel 21.

The first charging mode can be a normal charging mode. The secondcharging mode can be a quick charging mode. In the normal charging mode,the power supply device outputs smaller current (usually lower than 2.5A) or adopts low power (usually lower than 15 W) to charge the batteryof the device to be charged. In the normal charging mode, charging fullya battery of high capacity (such as a 3000 mA battery) usually takesseveral hours. In the quick charging mode, the power supply device canoutput greater current (usually higher than 2.5 A, such as 4.5 A, 5 A,or even higher) or adopt higher power (usually higher than or equal to15 W) to charge the battery of the device to be charged. Compared withthe normal charging mode, in the quick charging mode, the power supplydevice can charge fully the battery of the same capacity within asubstantially shorter charging period and at a higher charging speed.

In addition, the communication control circuit 23 can be configured toconduct two-way communication with the power supply device 10 (that is,communicate bi-directionally), to control output of the power supplydevice 10 in the second charging mode, that is, to control the chargingvoltage and/or charging current provided by the power supply device 10in the second charging mode. The device to be charged 40 can include acharging interface. The communication control circuit 23 communicateswith the power supply device 10 through a data line of the charginginterface. For instance, the charging interface can be a USB interface.The data line can be a D+ line and/or a D− line of the USB interface.Alternatively, the device to be charged 40 can also be configured toconduct wireless communication with the power supply device 10.

Content communicated between the power supply device 10 and thecommunication control circuit 23 and control manners of thecommunication control circuit 23 on output of the power supply device 10in the second charging mode are not limited herein. For example, thecommunication control circuit 23 can communicate with the power supplydevice 10, interact with present total voltage and/or present power ofthe battery 30 of the device to be charged 40, and adjust output-voltageand/or output-current of the power supply device 10 according to thepresent total voltage and/or present power of the battery 30. Thefollowing will describe in detail the content communicated between thecommunication control circuit 23 and the power supply device 10 and thecontrol manners of the communication control circuit 23 on output of thepower supply device 10 in the second charging mode in conjunction withimplementations of the disclosure.

Description above does not limit master-slave relationship between thepower supply device 10 and the device to be charged (or thecommunication control circuit 23 of the device to be charged). That isto say, any one of the power supply device 10 and the device to becharged can function as a master device to initiate a two-waycommunication, and correspondingly the other one of the power supplydevice 10 and the device to be charged can function as a slave device tomake a first response or a first reply to the communication initiated bythe master device. As a practical manner, identities of the masterdevice and the slave device can be determined by comparing levels of thepower supply device 10 and the device to be charged with reference toearth in a communication process.

The implementation of the two-way communication between the power supplydevice 10 and the device to be charged is not limited herein. In otherwords, any one of the power supply device 10 and the device to becharged can function as the master device to initiate the communication,and correspondingly the other one of the power supply device 10 and thedevice to be charged can function as the slave device to make the firstresponse or the first reply to the communication initiated by the masterdevice. Besides, the master device can make a second response to thefirst response or the first reply of the slave device, as such, themaster device and the slave device complete a negotiation on chargingmodes. As a possible implementation, charging between the master deviceand the slave device can be executed after completion of multiplenegotiations on charging modes between the master device and the slavedevice, so as to guarantee that the charging process is safe andreliable after negotiation.

The master device can make the second response to the first response orthe first reply to the communication of the slave device as follows. Themaster device receives from the slave device the first response or thefirst reply to the communication and make the second response to thefirst response or the first reply of the slave device. As an example,when the master device receives from the slave device the first responseor the first reply to the communication within a preset time period, themaster device can make the second response to the first response or thefirst reply of the slave device as follows. The master device and theslave device complete a negotiation on charging modes. Charging betweenthe master device and the slave device is executed in the first chargingmode or in the second charging mode according to the negotiation result,that is, the power supply device 10 is operable in the first chargingmode or in the second charging mode to charge the device to be chargedaccording to the negotiation.

The master device can make the second response to the first response orthe first reply to the communication of the slave device as follows.When the master device fails to receive from the slave device the firstresponse or the first reply to the communication within a preset timeperiod, the master device can still make the second response to thefirst response or the first reply made by the slave device. As anexample, when the master device fails to receive from the slave devicethe first response or the first reply to the communication within apreset time period, the master device can still make the second responseto the first response or the first reply made by the slave device asfollows: the master device and the slave device complete a negotiationon charging modes. Charging is executed in the first charging modebetween the master device and the slave device, that is, the powersupply device is operable in the first charging mode to charge thedevice to be charged.

Optionally, in some implementations, after the device to be charged, asthe master device, initiates the communication and the power supplydevice 10, as the slave device, makes the first response or the firstreply to the communication initiated by the master device, without thedevice to be charged making the second response to the first response orthe first reply of the power supply device 10, it can be regarded as themaster device and the slave device completing a negotiation on chargingmodes, and thus the power supply device 10 can determine to charge thedevice to be charged in the first charging mode or in the secondcharging mode according to the negotiation.

Optionally, in some implementations, the communication control circuit23 conducts two-way communication with the power supply device 10, so asto control output of the power supply device 10 in the second chargingmode as follows. The communication control circuit 23 conducts two-waycommunication with the power supply device 10, so as to negotiatecharging modes between the power supply device 10 and the device to becharged.

Optionally, in some implementations, the communication control circuit23 conducts two-way communication with the power supply device 10 tonegotiate charging modes between the power supply device 10 and thedevice to be charged as follows. The communication control circuit 23receives a first instruction from the power supply device 10, the firstinstruction is for enquiring whether the device to be charged enables(in other words, switches on) the second charging mode; thecommunication control circuit 23 sends a reply instruction of the firstinstruction to the power supply 10, the reply instruction of the firstinstruction is for indicating whether the device to be charged agrees toenable the second charging mode; in case that the device to be chargedagrees to enable the second charging mode, the communication controlcircuit 23 controls the power supply device 10 to charge the battery 30though the first charging channel 21.

Optionally, in some implementations, the communication control circuit23 conducts two-way communication with the power supply device 10 tocontrol output of the power supply device 10 in the second charging modeas follows. The communication control circuit 23 conducts two-waycommunication with the power supply device 10, so as to determinecharging voltage which is output by the power supply device in thesecond charging mode and for charging the device to be charged.

Optionally, in some implementations, the communication control circuit23 conducts two-way communication with the power supply device 10, so asto determine charging voltage which is output by the power supply devicefor charging the device to be charged as follows. The communicationcontrol circuit 23 receives a second instruction from the power supplydevice 10, the second instruction is for enquiring whether the chargingvoltage output by the power supply device 10 matches present totalvoltage of the battery 30 of the device to be charged; the communicationcontrol circuit 23 sends a reply instruction of the second instructionto the power supply 10, the reply instruction of the second instructionis for indicating that the voltage output by the power supply device 10matches the present total voltage of the battery 30 or does not match,that is, is at higher levels, or is at lower levels. Alternatively, thesecond instruction can be for enquiring whether it is suitable to usepresent output-voltage of the power supply device 10 as the chargingvoltage, which is output by the power supply device 10 in the secondcharging mode for charging the device to be charged. The replyinstruction of the second instruction is for indicating whether thepresent output-voltage of the power supply device 10 is suitable orunsuitable, that is, at higher levels or at lower levels. The presentoutput-voltage of the power supply device 10 matching the present totalvoltage of the battery 30, or the present output-voltage of the powersupply device 10 being suitable to be used as the charging voltage whichis output by the power supply device 10 in the second charging mode forcharging the device to be charged can be understood as follows. Thepresent output-voltage of the power supply device 10 is slightly higherthan the present total voltage of the battery, and the differencebetween the output-voltage of the power supply device 10 and the presenttotal voltage of the battery is within a preset range (usually at alevel of several hundred millivolts (mV)).

Optionally, in some implementations, the communication control circuit23 can conduct two-way communication with the power supply device 10, soas to control output of the power supply device 10 in the secondcharging mode as follows. The communication control circuit 23 conductstwo-way communication with the power supply device 10, so as todetermine charging current which is output by the power supply device 10in the second charging mode for charging the device to be charged.

Optionally, in some implementations, the communication control circuit23 can conduct two-way communication with the power supply device 10 todetermine charging current which is output by the power supply device 10in the second charging mode for charging the device to be charged asfollows. The communication control circuit 23 receives a thirdinstruction sent by the power supply device 10, the third instruction isfor enquiring a maximum charging current the device to be chargedsupports; the communication control circuit 23 sends a reply instructionof the third instruction to the power supply device 10, the replyinstruction of the third instruction is for indicating the maximumcharging current the device to be charged supports, so that the powersupply device 10 can determine the charging current which is output bythe power supply device 10 in the second charging mode for charging thedevice to be charged, according to the maximum charging current thedevice to be charged supports. It should be understood that, thecommunication control circuit 23 determining the charging current whichis output by the power supply device 10 in the second charging mode forcharging the device to be charged according to the maximum chargingcurrent the device to be charged supports can be implemented in variousmanners. For example, the power supply device 10 can determine themaximum charging current the device to be charged supports as thecharging current which is output by the power supply device 10 in thesecond charging mode for charging the device to be charged, orcomprehensively take into account the maximum charging current thedevice to be charged supports and other factors such as current outputcapability of the power supply device 10 itself to determine thecharging current which is output by the power supply device 10 in thesecond charging mode for charging the device to be charged.

Optionally, in some implementations, the communication control circuit23 conducts two-way communication with the power supply device 10 tocontrol output of the power supply device 10 in the second charging modeas follows. The communication control circuit 23 conducts two-waycommunication with the power supply device 10 to adjust output-currentof the power supply device 10 in the second charging mode.

Specifically, the communication control circuit 23 conducts two-waycommunication with the power supply device 10 to adjust theoutput-current of the power supply device 10 as follows. Thecommunication control circuit 23 receives a fourth instruction from thepower supply device 10, the fourth instruction is for enquiring presenttotal voltage of the battery; the communication control circuit 23 sendsa reply instruction of the fourth instruction to the power supply device10, the reply instruction of the fourth instruction is for indicatingthe present total voltage of the battery, so that the power supplydevice 10 can adjust the output-current of the power supply device 10according to the present total voltage of the battery.

Optionally, in some implementations, the communication control circuit23 conducts two-way communication with the power supply device 10, so asto control output of the power supply device 10 in the second chargingmode as follows. The communication control circuit 23 conducts two-waycommunication with the power supply device 10 to determine whether thereis contact failure in a charging interface.

Specifically, the communication control circuit 23 can conduct two-waycommunication with the power supply device 10 to determine whether thereis contact failure in the charging interface as follows. Thecommunication control circuit 23 receives a fourth instruction sent bythe power supply device 10, the fourth instruction is for enquiringpresent voltage of the battery of the device to be charged; thecommunication control circuit 23 sends a reply instruction of the fourthinstruction to the power supply device 10, the reply instruction of thefourth instruction is for indicating the present voltage of the batteryof the device to be charged, so that the power supply device 10 candetermine whether there is contact failure in the charging interfaceaccording to output-voltage of the power supply 10 and the presentvoltage of the battery of the device to be charged. For instance, incase that the power supply device 10 determines that difference betweenthe output-voltage of the power supply 10 and the present voltage of thebattery of the device to be charged is greater than a preset voltagethreshold value, it indicates that impedance, which is obtained by thedifference (that is, the difference between the output-voltage of thepower supply 10 and the present voltage of the battery of the device tobe charged) divided by output-current of the power supply device 10, isgreater than a preset impedance threshold value, it can be determinedthat there is contact failure in the charging interface.

Optionally, in some implementations, contact failure in the charginginterface can be determined by the device to be charged. For example,the communication control circuit 23 sends a sixth instruction to thepower supply device 10, the sixth instruction is for enquiringoutput-voltage of the power supply device 10; the communication controlcircuit 23 receives a reply instruction of the sixth instruction fromthe power supply device 10, the reply instruction of the sixthinstruction is for indicating the output-voltage of the power supplydevice 10, the communication control circuit 23 determines whether thereis contact failure in the charging interface according to presentvoltage of the battery and the output-voltage of the power supply 10.When the communication control circuit 23 determines that there iscontact failure in the charging interface, the communication controlcircuit 23 can send a fifth instruction to the power supply device 10,the fifth instruction is for indicating contact failure in the charginginterface. After receiving the fifth instruction, the power supplydevice 10 can exit the second charging mode.

The following will describe in detail a communication process betweenthe power supply device 10 and the device to be charged 40 (thecommunication control circuit 23 of the device to be charged 40, to bespecific) in conjunction with FIG. 10. It should be noted that, theexample of FIG. 10 is just for those skilled in the art to understandthe implementations of the disclosure, instead of limiting theimplementations of the disclosure to specific numeric values or specificsituations of the example. Those skilled in the art can make variousequivalent modifications and changes without departing from the scope ofthe implementation of the disclosure.

As illustrated in FIG. 10, the communication procedure between the powersupply device 10 and the device to be charged 40 (also referred to asthe communication procedure of a quick charging process) can include thefollowing five stages.

Stage 1:

After the device to be charged 40 is coupled with the power supplydevice 10, the device to be charged 40 can detect the type of the powersupply device 10 though data line D+ and data line D−. When the powersupply device 10 is detected to be a power supply device speciallyconfigured to charge such as an adaptor, current absorbed by the deviceto be charged 40 can be greater than a preset current threshold value 12(can be 1 A, for example). When the power supply device 10 detects thatoutput-current of the power supply device 10 is greater than or equal to12 within a preset duration (can be a continuous time period T1, forexample), the power supply device 10 can consider that identification ofthe type of the power supply device by the device to be charged 40 iscompleted. Next, the power supply device 10 begins a negotiation processwith the device to be charged 40 and send Instruction 1 (correspondingto the first instruction mentioned above), so as to enquire whether thedevice to be charged 40 agrees to be charged by the power supply device10 in the second charging mode.

When the power supply device 10 receives a reply instruction ofInstruction 1 and the reply instruction of Instruction 1 indicates thatthe device to be charged 40 disagrees to be charged by the power supplydevice 10 in the second charging mode, the power supply device 10detects once again the output-current of the power supply device 10.When the output-current of the power supply device 10 is still greaterthan or equal to 12 within a preset continuous duration (can be acontinuous time period T1), the power supply device 10 sends once againInstruction 1 to enquire whether the device to be charged 40 agrees tobe charged by the power supply device 10 in the second charging mode.The power supply device 10 repeats the above operations at Stage 1 untilthe device to be charged 40 agrees to be charged by the power supplydevice 10 in the second charging mode, or the output-current of thepower supply device 10 is no longer greater than or equal to 12.

When the device to be charged 40 agrees to be charged by the powersupply device 10 in the second charging mode, the communicationprocedure proceeds to Stage 2.

Stage 2:

The output-voltage of the power supply device 10 can include multiplegrades. The power supply device 10 sends Instruction 2 (corresponding tothe second instruction mentioned above) to enquire whether theoutput-voltage of the power supply device 10 (present output-voltage)matches present voltage of the battery 30 of the device to be charged40.

The device to be charged 40 sends a reply instruction of Instruction 2to indicate whether the output-voltage of the power supply device 10matches the present voltage of the battery 30 of the device to becharged 40, is at higher levels, or is at lower levels. When the replyinstruction of Instruction 2 indicates that the output-voltage of thepower supply device 10 is at higher levels or is at lower levels, thepower supply device 10 can adjust the output-voltage of the power supplydevice 10 by one grade and send once again Instruction 2 to the deviceto be charged 40 to enquire whether the output-voltage of the powersupply device 10 matches the present voltage of the battery. Repeat theabove steps until the device to be charged 40 determines that theoutput-voltage of the power supply device 10 matches the present voltageof the battery 30 of the device to be charged 40 and proceed to Stage 3.

Stage 3:

The power supply device 10 sends Instruction 3 (corresponding to thethird instruction mentioned above) to enquire a maximum charging currentthe device to be charged 40 supports. The device to be charged 40 sendsa reply instruction of Instruction 3 to indicate the maximum chargingcurrent the device to be charged 40 supports. Proceed to Stage 4.

Stage 4:

The power supply device 10 determines, according to the maximum chargingcurrent the device to be charged 40 supports, the charging current whichis output by the power supply device 10 in the second charging mode forcharging the device to be charged 40. Proceed to Stage 5, that is, theconstant-current charging stage.

Stage 5:

After proceeding to the constant-current charging stage, the powersupply device 10 can send Instruction 4 (corresponding to the fourthinstruction mentioned above) to the device to be charged 40 at certaintime intervals, so as to enquire present voltage of the battery 30 ofthe device to be charged 40. The device to be charged 40 can send areply instruction of Instruction 4 to feed back the present voltage ofthe battery. The power supply device 10 can determine whether thecharging interface is in a good contact and whether it is necessary toreduce the output-current of the power supply device 10, according tothe present voltage of the battery. When the power supply device 10determines that there is contact failure in the charging interface, thepower supply device 10 can send Instruction 5 (corresponding to thefifth instruction mentioned above), thereby exiting the second chargingmode and being reset to return to Stage 1.

Optionally, in some implementations, at Stage 1, when the device to becharged 40 sends the reply instruction of Instruction 1, the replyinstruction of Instruction 1 can carry path impedance data (orinformation) of the device to be charged 40. The path impedance data ofthe device to be charged 40 can be configured to determine whether thecharging interface is in a good contact in the stage five.

Optionally, in some implementations, at Stage 2, duration from when thedevice to be charged 40 agrees to be charged by the power supply device10 in the second charging mode to when the power supply device 10adjusts the output-voltage thereof to a suitable charging voltage can becontrolled within a certain range. When the duration is beyond thecertain range, the power supply device 10 or the device to be charged 40can determine that the communication process is abnormal, being reset toreturn to Stage 1.

Optionally, in some implementations, at Stage 2, when the output-voltageof the power supply device 10 is higher than the present voltage of thebattery of the device to be charged 40 by ΔV (ΔV can be set between 200mV and 500 mV), the device to be charged 40 can send the replyinstruction of Instruction 2 to indicate that the output-voltage of thepower supply device 10 matches the voltage of the battery of the deviceto be charged 40.

Optionally, in some implementations, at Stage 4, adjusting speed of theoutput-current of the power supply device 10 can be controlled within acertain range, so as to avoid abnormality of the charging processresulting from excessively high adjusting speed.

Optionally, in some implementations, at Stage 5, change magnitude of theoutput-current of the power supply device 10 can be controlled within5%.

Optionally, in some implementations, at Stage 5, the power supply device10 can detect in real time impedance of charging path. Specifically, thepower supply device 10 can detect the impedance of charging pathaccording to the output-voltage and the output-current of the powersupply device 10 and the present voltage of the battery fed back by thedevice to be charged 40. When the impedance of charging path is higherthan the impedance of path of the device to be charged 40 plus impedanceof a charging cable, it indicates that there is contact failure in thecharging interface, and thus the power supply device 10 stops chargingthe device to be charged 40 in the second charging mode.

Optionally, in some implementations, after the power supply device 10enables the second charging mode to charge the device to be charged 40,time intervals of communication between the power supply device 10 andthe device to be charged 40 can be controlled within a certain range, toavoid abnormality of communication resulting from excessively short timeintervals of communication.

Optionally, in some implementations, stopping of the charging process(or stopping of the power supply device 10 charging the device to becharged 40 in the second charging mode) can include a recoverablestopping and a non-recoverable stopping.

For example, when it is detected that the battery of the device to becharged 40 is fully charged or there is contact failure in the charginginterface, the charging process stops, a charging communication processis reset, and the charging process enters again Stage 1. Then, when thedevice to be charged 40 disagrees to be charged by the power supplydevice 10 in the second charging mode, the communication procedure willnot proceed to Stage 2. The stopping of the charging process in thiscase can be considered as the non-recoverable stopping.

For another example, when there is abnormality of the communicationbetween the power supply device 10 and the device to be charged 40, thecharging process stops, the charging communication process is reset, andthe charging process enters again Stage 1. After requirements on Stage 1are satisfied, the device to be charged 40 agrees to be charged by thepower supply device 10 in the second charging mode, so as to recover thecharging process. The stopping of the charging process in this case canbe considered as the recoverable stopping.

For yet another example, when the device to be charged 40 detectsabnormality of the battery, the charging process stops, is reset, andenters again Stage 1. Then, the device to be charged 40 disagrees to becharged by the power supply device 10 in the second charging mode. Afterthe battery returns to normal and the requirements on Stage 1 aresatisfied, the device to be charged 40 agrees to be charged by the powersupply device 10 in the second charging mode. The stopping of the quickcharging process in this case can be considered as the recoverablestopping.

The above communication steps or operations of FIG. 10 are justillustrative. For instance, at Stage 1, after the device to be charged40 is coupled with the power supply device 10, handshake communicationbetween the device to be charged 40 and the power supply device 10 canalso be initiated by the device to be charged 40. In other words, thedevice to be charged 40 sends Instruction 1, to enquire whether thepower supply device 10 enables the second charging mode. Thereafter, thedevice to be charged 40 receives a reply instruction from the powersupply device 10 indicating that the power supply device 10 agrees tocharge the device to be charged 40 in the second charging mode. Aftersending the reply instruction responsive to Instruction 1, the powersupply device 10 begins to charge the battery of the device to becharged 40 in the second charging mode.

For another instance, after Stage 5, the communication procedure canfurther include the constant-voltage charging stage. Specifically, inStage 5, the device to be charged 40 can feed back the present voltageof the battery to the power supply device 10. When the present voltageof the battery reaches a threshold value of charging voltage in theconstant-voltage charging stage, the charging stage turns to theconstant-voltage charging stage from the constant-current chargingstage. In the constant-voltage charging stage, the charging currentgradually decreases. When the charging current decreases to a certainthreshold value, it indicates that the battery of the device to becharged 40 is fully charged, and thus the whole charging process iscompleted and stopped.

Apparatus implementations of the disclosure are described in detailabove in conjunction with FIG. 1 to FIG. 10. The following will describein detail method implementations of the disclosure in conjunction withFIG. 11. It should be understood that, description of method anddescription of apparatus correspond to each other. For simplicity,repeated description will be properly omitted.

FIG. 11 is a schematic flowchart illustrating a battery managementmethod according to an implementation of the present disclosure. Thebattery management method of FIG. 11 is applicable to a batterymanagement circuit. The battery management circuit can be, for example,the battery management circuit 20 described above. The batterymanagement circuit can include a first charging channel and a Cukcircuit. Charging voltage and/or charging current is received from apower supply device through the first charging channel and is providedto a battery directly through the first charging channel, and thebattery includes a first cell and a second cell coupled in series. Thebattery management circuit may further include a communication controlcircuit, which is configured to communicate with the power supply deviceand internal components of the battery management circuit.

The battery management method includes operations at blocks 1110 to1120. The following will describe each of the operations of FIG. 11 indetail.

At block 1110, communicate with the power supply device, to makemagnitude of the charging voltage and/or charging current match apresent charging stage of the battery, when the power supply devicecharges the battery through the first charging channel. This process canbe conducted by the battery management circuit.

At block 1120, send a drive signal to the Cuk circuit to drive the Cukcircuit to work, to make energy of the first cell and the second cell betransferred through the Cuk circuit to balance voltage of the first celland voltage of the second cell, when the voltage of the first cell andthe voltage of second cell are unbalanced. This process can be conductedby the battery management circuit.

Optionally, in some implementations, before sending the drive signal tothe Cuk circuit to drive the Cuk circuit to work, the battery managementmethod can further include the following: acquire present power and/orpresent voltage of the first cell and present power and/or presentvoltage of the second cell. The sending the drive signal to the Cukcircuit to drive the Cuk circuit to work includes the following: sendthe drive signal to the Cuk circuit to drive the Cuk circuit to workwhen a difference between the present power and/or present voltage ofthe first cell and the present power and/or present voltage of thesecond cell is greater than a preset threshold value.

Optionally, in some implementations, the battery management methodfurther includes the following: adjust duty cycle of the drive signal toadjust current in the Cuk circuit, during working of the Cuk circuit.

Optionally, in some implementations, the battery management circuitfurther includes a current detecting circuit configured to detect thecurrent in the Cuk circuit. The adjusting the duty cycle of the drivesignal to adjust the current in the Cuk circuit includes the following:determine a target value of the current in the Cuk circuit according tothe difference between the present power and/or present voltage of thefirst cell and the present power and/or present voltage of the secondcell; adjust the duty cycle of the drive signal to make the current inthe Cuk circuit detected by the current detecting circuit reach thetarget value.

Optionally, in some implementations, the battery management circuit canfurther include a second charging channel provided with a boost circuit,and the boost circuit is configured to receive initial voltage from thepower supply device and increase the initial voltage to a target voltageto charge the battery according to the target voltage, when the powersupply device charges the battery through the second charging channel.The initial voltage is lower than total voltage of the battery and thetarget voltage is higher than the total voltage of the battery. Thebattery management method can further include the following: controlswitching between the first charging channel and the second channel.

The above identified various processes can be conducted by thecommunication control circuit.

Those of ordinary skill in the art will appreciate that units (includingsub-units) and algorithmic operations of various examples described inconnection with implementations herein can be implemented by electronichardware or by a combination of computer software and electronichardware. Whether these functions are performed by means of hardware orsoftware depends on the application and the design constraints of theassociated technical solution. A professional technician may usedifferent methods with regard to each particular application toimplement the described functionality, but such methods should not beregarded as lying beyond the scope of the disclosure.

It will be evident to those skilled in the art that the correspondingprocesses of the above method implementations can be referred to for theworking processes of the foregoing systems, apparatuses, and units, forpurposes of convenience and simplicity and will not be repeated herein.

It will be appreciated that the systems, apparatuses, and methodsdisclosed in implementations herein may also be implemented in variousother manners. For example, the above apparatus implementations aremerely illustrative, e.g., the division of units (including sub-units)is only a division of logical functions, and there may exist other waysof division in practice, e.g., multiple units (including sub-units) orcomponents may be combined or may be integrated into another system, orsome features may be ignored or not included. In other respects, thecoupling or direct coupling or communication connection as illustratedor discussed may be an indirect coupling or communication connectionthrough some interface, device or unit, and may be electrical,mechanical, or otherwise.

Separated units (including sub-units) as illustrated may or may not bephysically separated. Components or parts displayed as units (includingsub-units) may or may not be physical units, and may reside at onelocation or may be distributed to multiple networked units. Some or allof the units (including sub-units) may be selectively adopted accordingto practical needs to achieve desired objectives of the disclosure.

Additionally, various functional units (including sub-units) describedin implementations herein may be integrated into one processing unit ormay be present as a number of physically separated units, and two ormore units may be integrated into one.

If the integrated units are implemented as software functional units andsold or used as standalone products, they may be stored in a computerreadable storage medium. Based on such an understanding, the essentialtechnical solution, or the portion that contributes to the prior art, orall or part of the technical solution of the disclosure may be embodiedas software products. Computer software products can be stored in astorage medium and may include multiple instructions that, whenexecuted, can cause a computing device, e.g., a personal computer, aserver, a second adapter, a network device, etc., to execute some or alloperations of the methods as described in the various implementations.The above storage medium may include various kinds of media that canstore program code, such as a USB flash disk, a mobile hard drive, aread-only memory (ROM), a random access memory (RAM), a magnetic disk,or an optical disk.

What is claimed is:
 1. A battery management circuit, comprising: a firstcharging channel, a Cuk circuit, and a communication control circuit,wherein at least one of charging voltage and charging current isreceived from a power supply device and applied directly to a batteryfor charging through the first charging channel, the battery comprisinga first cell and a second cell coupled in series, wherein the at leastone of the charging voltage and the charging current received from thepower supply device is applied directly to the battery without beingconverted; and the communication control circuit is configured to:communicate with the power supply device to make a magnitude of at leastone of the charging voltage and the charging current received from thepower supply device match a present charging stage of the battery, whenthe power supply device charges the battery through the first chargingchannel, wherein the present charging stage of the battery is any one ofa trickle charging stage, a constant-current charging stage, and aconstant-voltage charging stage; and send a drive signal to the Cukcircuit to drive the Cuk circuit to work, to make energy of the firstcell and the second cell be transferred through the Cuk circuit tobalance voltage of the first cell and voltage of the second cell, whenthe voltage of the first cell and the voltage of second cell areunbalanced.
 2. The battery management circuit of claim 1, wherein thecommunication control circuit is further configured to acquire at leastone of present power and present voltage of the first cell, and at leastone of present power and present voltage of the second cell, before thedrive signal is sent to the Cuk circuit to drive the Cuk circuit towork, and wherein the communication control circuit configured to sendthe drive signal to the Cuk circuit to drive the Cuk circuit to work isconfigured to: send the drive signal to the Cuk circuit to drive the Cukcircuit to work when a difference between at least one of the presentpower and the present voltage of the first cell, and at least one of thepresent power and the present voltage of the second cell is greater thana preset threshold value.
 3. The battery management circuit of claim 1,wherein the communication control circuit is further configured toadjust duty cycle of the drive signal to adjust current in the Cukcircuit, during working of the Cuk circuit.
 4. The battery managementcircuit of claim 3, further comprising a current detecting circuitconfigured to detect the current in the Cuk circuit, wherein thecommunication control circuit configured to adjust the duty cycle of thedrive signal, to adjust the current of the Cuk circuit is configured to:determine a target value of the current in the Cuk circuit, according tothe difference between at least one of the present power and the presentvoltage of the first cell and at least one of the present power and thepresent voltage of the second cell, and adjust the duty cycle of thedrive signal to make the current in the Cuk circuit detected by thecurrent detecting circuit reach the target value.
 5. The batterymanagement circuit of claim 1, further comprising a second chargingchannel provided with a boost circuit, wherein the boost circuit isconfigured to receive initial voltage from the power supply device andincrease the initial voltage to a target voltage to charge the batteryaccording to the target voltage, when the power supply device chargesthe battery through the second charging channel, the initial voltagebeing lower than total voltage of the battery and the target voltagebeing higher than the total voltage of the battery.
 6. The batterymanagement circuit of claim 5, wherein the communication control circuitis further configured to control switching between the first chargingchannel and the second charging channel.
 7. The battery managementcircuit of claim 5, wherein the first charging channel is provided witha switch transistor to control switching between the first chargingchannel and the second charging channel.
 8. The battery managementcircuit of claim 1, wherein the Cuk circuit comprises at least oneswitch transistor, a first inductor and a second inductor, and acapacitor coupled between the first inductor and the second inductor,the first inductor is further coupled with a positive electrode of thefirst cell and the second inductor is further coupled with a negativeelectrode of the second cell, and the at least one switch transistor hasone end coupled between the capacitor and one inductor and another endcoupled with an electrode of the first cell or the second cell.
 9. Thebattery management circuit of claim 8, wherein the at least one switchtransistor comprises a first switch transistor and a second switchtransistor, the first switch transistor has one end coupled between thecapacitor and the first inductor, another end coupled with a negativeelectrode of the first cell, and still another end coupled with thecommunication control circuit; the second switch transistor has one endcoupled between the capacitor and the second inductor, another endcoupled with a positive electrode of the second cell, and still anotherend coupled with the communication control circuit; and thecommunication control circuit is configured to send the drive signal tothe first switch transistor and the second switch transistorrespectively in a predetermined time sequence to control direction andspeed of energy transfer between the first cell and the second cell. 10.A device to be charged, comprising: a battery, comprising a first celland a second cell coupled in series; and a battery management circuit,comprising a first charging channel, a Cuk circuit, and a communicationcontrol circuit, wherein the first charging channel, through which atleast one of charging voltage and charging current is received from apower supply device and applied directly to the battery for charging theat least one of the charging voltage and the charging current receivedfrom the power supply device is applied directly to the battery withoutbeing converted; the communication control circuit is configured tocommunicate with the power supply device to make a magnitude of at leastone of the charging voltage and the charging current from the powersupply device match a present charging stage of the battery, when thepower supply device charges the battery through the first chargingchannel, the present charging stage of the battery is any one of atrickle charging stage, a constant-current charging stage, and aconstant-voltage charging stage; and the communication control circuitis further configured to send a drive signal to the Cuk circuit to drivethe Cuk circuit to work, to make energy of the first cell and the secondcell be transferred through the Cuk circuit to balance voltage of thefirst cell and voltage of the second cell, when the voltage of the firstcell and the voltage of second cell are unbalanced.
 11. The device ofclaim 10, wherein the communication control circuit is furtherconfigured to acquire at least one of present power and present voltageof the first cell and at least one of present power and present voltageof the second cell before the drive signal is sent to the Cuk circuit todrive the Cuk circuit to work; and the communication control circuitconfigured to send the drive signal to the Cuk circuit to drive the Cukcircuit to work is configured to: send the drive signal to the Cukcircuit to drive the Cuk circuit to work when a difference between atleast one of the present power and the present voltage of the firstcell, and at least one of the present power and the present voltage ofthe second cell is greater than a preset threshold value.
 12. The deviceof claim 10, wherein the communication control circuit is furtherconfigured to adjust duty cycle of the drive signal to adjust current inthe Cuk circuit, during working of the Cuk circuit.
 13. The device ofclaim 12, wherein the battery management circuit further comprises acurrent detecting circuit configured to detect the current in the Cukcircuit; and the communication control circuit configured to adjust theduty cycle of the drive signal, to adjust the current of the Cuk circuitis configured to: determine a target value of the current in the Cukcircuit, according to the difference between at least one of the presentpower and the present voltage of the first cell, and at least one of thepresent power and the present voltage of the second cell; and adjust theduty cycle of the drive signal to make the current in the Cuk circuitdetected by the current detecting circuit reach the target value. 14.The device of claim 10, wherein the battery management circuit furthercomprises a second charging channel provided with a boost circuit; theboost circuit is configured to receive initial voltage from the powersupply device and increase the initial voltage to a target voltage tocharge the battery according to the target voltage, when the powersupply device charges the battery through the second charging channel;the initial voltage is lower than total voltage of the battery and thetarget voltage being higher than the total voltage of the battery; andthe communication control circuit is further configured to controlswitching between the first charging channel and the second chargingchannel.
 15. A method for battery management, comprising: communicatingwith a power supply device to make a magnitude of at least one ofcharging voltage and charging current provided by the power supplydevice match a present charging stage of a battery, when the powersupply device charges the battery through a first charging channeldirectly, the battery comprising a first cell and a second cell coupledin series wherein the at least one of the charging voltage and thecharging current received from the power supply device is applieddirectly to the battery without being converted, and the presentcharging stage of the battery is any one of a trickle charging stage, aconstant-current charging stage, and a constant-voltage charging stage;and sending a drive signal to a Cuk circuit to drive the Cuk circuit towork, to make energy of the first cell and the second cell betransferred through the Cuk circuit to balance voltage of the first celland voltage of the second cell, when the voltage of the first cell andthe voltage of second cell are unbalanced.
 16. The method of claim 15,further comprising: before sending the drive signal to the Cuk circuitto drive the Cuk circuit to work, acquiring at least one of presentpower and present voltage of the first cell, and at least one of presentpower and present voltage of the second cell, wherein sending the drivesignal to the Cuk circuit to drive the Cuk circuit to work comprises:sending the drive signal to the Cuk circuit to drive the Cuk circuit towork when a difference between at least one of the present power and thepresent voltage of the first cell and at least one of the present powerand the present voltage of the second cell is greater than a presetthreshold value.
 17. The method of claim 15, further comprising:adjusting duty cycle of the drive signal to adjust current in the Cukcircuit, during working of the Cuk circuit.
 18. The method of claim 17,wherein adjusting the duty cycle of the drive signal to adjust thecurrent in the Cuk circuit comprises: determining a target value of thecurrent in the Cuk circuit according to the difference between at leastone of the present power and the present voltage of the first cell andat least one of the present power and the present voltage of the secondcell; and adjusting the duty cycle of the drive signal to make thecurrent in the Cuk circuit reach the target value.
 19. The method ofclaim 15, wherein the battery management circuit further comprises asecond charging channel, the second charging channel is provided with aboost circuit, and the boost circuit is configured to receive initialvoltage from the power supply device and increase the initial voltage toa target voltage to charge the battery based on the target voltage, whenthe power supply device charges the battery through the second chargingchannel, wherein the initial voltage is lower than total voltage of thebattery and the target voltage is higher than the total voltage of thebattery.
 20. The method of claim 19, further comprising: controllingswitching between the first charging channel and the second channel.